Singleton Integer Issue

Question

Hi

I have a singleton which I hold a single integer in, my score. However when I load it form the singleton in a another view it doesn't show what I want but instead sticks at a wired 6592960. Any ideas why? Something to do with how I am using @property Im thinking, what the correct way to @property an int?

Thanks.

EDIT: Code: Singleton .h

#import <Foundation/Foundation.h>


@interface scoreData : NSObject {

    int score;
}

@property int score;

+ (scoreData *)sharedData;

@end

Singleton .m

#import "scoreData.h"


static scoreData *sharedData = nil;

@implementation scoreData

@synthesize score;

#pragma mark -
#pragma mark Singleton Methods
+ (scoreData *)sharedData {
    if(sharedData == nil){
        sharedData = [[super allocWithZone:NULL] init];
    }
    return sharedData;
}
+ (id)allocWithZone:(NSZone *)zone {
    return [[self sharedManager] retain];
}
- (id)copyWithZone:(NSZone *)zone {
    return self;
}
- (id)retain {
    return self;
}
- (unsigned)retainCount {
    return NSUIntegerMax;
}
- (void)release {
    //do nothing
}
- (id)autorelease {
    return self;
}

@end

Inside my other view, I access like this and then try and change the number and of course I import the singleton:

scoreData *score = [scoreData sharedData];
score.score = 0;

Answer 1

If it's a true singleton, then you can have your getter and setter simply directly access an initialized static global variable, and skip all the runtime alloc and zone busywork.

Answer 2

I would write the @property like this:

@property (nonatomic,assign) int score;

Also i would change sharedData:

+ (scoreData *)sharedData {
    if( sharedData == nil ){
        sharedData = [[self alloc] init];
    }
    return sharedData;
}

Edit: I tried your code and got EXC_BADACCESS because it went recursive here:

+ (id)allocWithZone:(NSZone *)zone {
    return [[self sharedManager] retain];
}

When i removed that method everything worked as expected.

Answer 3

MySingleton.h

#import <Foundation/Foundation.h>

@interface MySingleton : NSObject {

}
@property(nonatomic,assign) int score;
+ (MySingleton*) sharedInstance;

@end

MySingleton.m

#import "MySingleton.h"

static MySingleton *_instance;
@implementation MySingleton
@synthesize score;

+ (MySingleton*)sharedInstance
{
    @synchronized(self) {
        if (_instance == nil) {
            _instance = [[super allocWithZone:NULL] init];
        }
    }
    return _instance;
}

#pragma mark Singleton Methods
+ (id)allocWithZone:(NSZone *)zone
{   
    return [[self sharedInstance]retain];   
}

- (id)copyWithZone:(NSZone *)zone
{
    return self;    
}

- (id)retain
{   
    return self;    
}

- (unsigned)retainCount
{
    return NSUIntegerMax; 
}

- (void)release
{
}

- (id)autorelease
{
    return self;    
}

@end

edit
See this xcode-template to simplify singleton-generation.